The present invention relates to a driving device for rolls in high speed rolling mills and the like.
A drive shaft for driving the rolls of a rolling mill, for example, couples together a drive shaft element and a driven shaft element, which is the roll neck portion of the rolling mill, and through universal joints included at two places in the drive shaft itself it also effects the centering of the drive and driven shaft elements and the transmission of torque. The drive shaft includes fitting yokes which form the opposite ends thereof and which are adapted to be fitted on the drive and driven shaft elements, whereby the drive shaft is connected to these shaft elements.
The serious drawback inherent in such conventional drive shaft lies in the fact that in order to facilitate the exchange (mounting and dismounting) of rolling mill rolls, the roll neck portion of the rolling mill, which is the driven shaft element, and the driven fitting yoke are fitted and coupled together withla clearance or play therebetween, said clearance resulting in a rotational vibration being exerted in the drive shaft, said rotational vibration being transmitted to the rolling mill roll and greately decreasing the accuracy of rolling while repeatedly imparting a vibratory impact to the bearings supporting the rolling mill roll and backup roll and hence damaging these bearings in a short period of time.
On the other hand, recent rolling mills are confronted by the important problems of speeding up the rolling operation and improving the rolling accuracy and the rate of operation. With the conventional drive shaft, however, the adverse influence of said vibration becomes more conspicuous with the speedup of the rolling mill and there are difficulties in providing a sufficient mechanical strength. If the roll neck and the fitting yoke are fitted together with an interference fit in order to eliminate said vibration, the exchange of rolls would become impossible. Thus, it has been impossible to solve said problems.